This invention relates to warm-air drying installations for drying hands or other parts of the body.
The invention is more particularly concerned with installations including several hand drying apparatus each of which receive air from the same air moving means.
One example of a previous installation is described in British Patent Application No. GB No. 2 137 878A in which a pedestal has eight or six hand drying outlets disposed about it. Such arrangements are advantageous because they only require one fan or other means for producing airflow, thereby leading to a compact, low-cost installation. In previous such installations, each outlet has a foot pedal, or similar switch, the operation of which opens a flap and turns on a heater associated with the outlet, so that warm air is blown out of the outlet over the user's hands. Difficulties, however, arise because the quantity of air needed to be produced by the fan will vary according to the number of apparatus in use at the time. If the fan is arranged to produce a constant total airflow there will be considerable differences in the airflow at any one outlet according to the number in use. It has been found impracticable to vary the total airflow produced by the fan, in order to maintain a constant flow at the outlets regardless of the number in use, since this requires very large speed variations of the fan and its driving motor. Also, this would result in a considerable loss of fan air pressure.
One solution of this problem is to arrange the installation such that air is blown out of all the apparatus outlets when any one apparatus is operated. However, if the air at all outlets is heated, this is wasteful. If, instead, only that outlet in use is heated and the others blow out unheated air, this will lead to draughts and will cause confusion to users since they may try to dry their hands at an outlet which is blowing out unheated air.